MJPEG View Controller

MJPEGViewController.m

//
//  MJPEGViewController.m
//  iMocs
//
//  Created by akh on 2018-10-29.
//  Copyright ? 2018 akh. All rights reserved.
//

#import "MJPEGViewController.h"

#define END_MARKER_BYTES { 0xFF, 0xD9 }

@interface MJPEGViewController ()
- (IBAction)reloadTouched:(id)sender;
@property (weak, nonatomic) IBOutlet UIView *connectedView;
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@property(strong, nonatomic) NSMutableData *buffer;
@property(strong, nonatomic) NSURLConnection *conn;
@property(strong, nonatomic) NSData *endMarkerData;
@end

@implementation MJPEGViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view.
  uint8_t endMarker[2] = END_MARKER_BYTES;
  self.endMarkerData = [[NSData alloc] initWithBytes:endMarker length:2];
}

- (void) play {
  self.buffer = [NSMutableData data];
  
  dispatch_sync(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^(void){
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.12.1:8080/?action=stream"]];
    
    self.conn = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
    [self.conn start];
    
  });
}

- (void) stop {
  [self.conn cancel];
  self.connectedView.backgroundColor = [UIColor redColor];
}

- (void) viewWillAppear:(BOOL)animated {
  [self play];
}

- (void)viewDidDisappear:(BOOL)animated {
  [self stop];
}

- (IBAction)reloadTouched:(id)sender {
  [self stop];
  [self play];
}

- (void) connection:(NSURLConnection *)connection didFailWithError:(nonnull NSError *)error {
  self.connectedView.backgroundColor = [UIColor redColor];
  self.buffer = nil;
  self.imageView.image = nil;
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
  [_buffer appendData:data];
  self.connectedView.backgroundColor = [UIColor greenColor];
  
  NSRange endRange = [_buffer rangeOfData:_endMarkerData
                                  options:0
                                    range:NSMakeRange(0, _buffer.length)];
  
  long long endLocation = endRange.location + endRange.length;
  if (_buffer.length >= endLocation) {
    NSData *imageData = [_buffer subdataWithRange:NSMakeRange(0, endLocation)];
    UIImage *receivedImage = [UIImage imageWithData:imageData];
    if (receivedImage) {
      //Background Thread
      dispatch_async(dispatch_get_main_queue(), ^(void){
        self.imageView.image = receivedImage;
      });
      
    }
  }
  
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
  //UIImage *img = [UIImage imageWithData:self.buffer];
  //self.imageView.image = img;
  [self.buffer setLength:0];
}

@end